High room-temperature TCR of La0.7(K0.25Sr0.05)MnO3:xAg2O composites obtained at optimized Ag2O ratio

In this study, La-0.7(K0.25Sr0.05)MnO3 (LKSMO) perovskites were prepared by the sol-gel method in the presence of different added Ag2O ratios to yield LKSMO:xAg(2)O composites. The structures of LKSMO:xAg(2)O were studied by X-ray diffraction (XRD), Raman, and Fourier transform infrared (FTIR) spectroscopy. The surface morphologies were characterized by scanning electron microscopy (SEM), elemental mapping, and energy dispersive spectrometry (EDS). The changes in the concentrations of Mn3+ and Mn4+ ions were examined by X-ray photoelectron spectroscopy (XPS). The results indicated that the addition of Ag2O led to the formation of a second phase (Ag) within the composites, occupying the A-site in LKSMO matrix by Ag+ ions. This structural change altered the magnetic and electric properties of LKSMO:xAg(2)O samples. The LKSMO:0.3Ag(2)O composite displayed the largest TCR and higher MR at room temperature compared to published literature. In sum, the magnetic and electric properties of LKSMO:xAg(2)O samples can be opti-mized by varying the amount of added Ag2O. (C) 2021 Elsevier B.V. All rights reserved.